Safety pressure switch

ABSTRACT

A safety pressure switch can be used with a gas appliance. The gas appliance can be a single fuel or a dual fuel appliance for use with one of a first fuel type or a second fuel type different than the first. The safety pressure switch can be fluidly connected to a fuel input and electrically coupled to a pilot assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/181,515, filed on Feb. 14, 2014, which claims priority to U.S. PatentAppl. No. 61/771,795, filed Mar. 2, 2013; 61/773,716, filed Mar. 6,2013; 61/773,713, filed Mar. 6, 2013; 61/778,072, filed Mar. 12, 2013;and 61/806,344, filed Mar. 28, 2013. The entire contents of the aboveapplications are hereby incorporated by reference and made a part ofthis specification. Any and all priority claims identified in theApplication Data Sheet, or any correction thereto, are herebyincorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE INVENTION

Field of the Invention

Certain embodiments disclosed herein relate generally to a heatingapparatus for use in a gas appliance adapted for single or multiple fueluse. The heating apparatus can be, can be a part of, and can be used inor with many different appliances, including, but not limited to:heaters, boilers, dryers, washing machines, ovens, fireplaces, stoves,water heaters, barbeques, etc.

Description of the Related Art

Many varieties of appliances, such as heaters, boilers, dryers, washingmachines, ovens, fireplaces, stoves, and other heat-producing devicesutilize pressurized, combustible fuels. Some such devices commonlyoperate with either liquid propane or natural gas. And some such devicesmay operate on one or more other fuels. However, such devices andcertain components thereof have various limitations and disadvantages.Therefore, there exists a constant need for improvement in appliancesand components to be used in appliances.

SUMMARY

According to some embodiments a heating system can include any number ofdifferent components such as a fuel selector valve, a pressureregulator, a control valve, a burner nozzle, a burner, a pilot, and/oran oxygen depletion sensor. In addition, a heating system can be asingle fuel, dual fuel or multi-fuel heating system. For example, theheating system can be configured to be used with one or more of naturalgas, liquid propane, well gas, city gas, and methane.

In some embodiments one or more of a safety pilot, a safety oxygendepletion sensor, a safety pressure switch, and a temperature sensor canbe used with a heating system. These safety features can be used tostop, or shut off fuel flow through the heating system, and/or preventfuel from flowing to a burner. In some embodiments, the safety featurecan be used to shut off flow through the control valve when an excessiveheat threshold or other condition is met. For example, if the wrong fuelis connected to the heating system a temperature or pressure conditioncan be detected and a signal generated. This signal may be sent to acontrol valve or a circuit board to close a valve, and/or initiate astop sequence. In some embodiments the signal may interrupt, reduce, orotherwise change a separate signal, such as for example, a currentgenerated at a thermocouple.

A pressure switch according to some embodiments can comprise a housinghaving an inlet and defining an internal chamber. A spring and adiaphragm connected to the spring can be positioned within the internalchamber such that fluid entering the inlet acts on the diaphragm. Thepressure switch can also include first and second electrical contactsand a movable contact member. The movable contact member can beconnected to the diaphragm such that movement of the diaphragm can causethe movable contact member to movably engage and disengage the first andsecond electrical contacts. The diaphragm and spring can be configuredto move the contact member between engaged and disengaged positions at aset fluid pressure. The movable contact member may be biased to eitherthe engaged or disengaged position.

A heater assembly may include a pressure switch. The heater assembly canalso include a burner, a first fuel hookup, a pilot nozzle, atemperature sensor, and a control valve for controlling the flow of fuelto said burner. The pressure switch can communicate with the first fuelhook-up, wherein a fuel at the fuel hookup has a pressure below athreshold, the pressure switch can permit the temperature sensor toelectrically connect with the control valve. When the fuel has apressure above the pressure threshold, the pressure switch can preventthe temperature sensor from electrically connecting with the controlvalve.

In some embodiments, a heater assembly can comprise a pressure switchand a thermocouple. The pressure switch can comprise a valve membermovable at a predetermined threshold pressure, first and secondelectrical contacts, and a movable contact member. The movable contactmember can be mechanically connected to the valve member and movabletherewith. The movable contact member can be configured for electricalconnection to the first and second electrical contacts when in a firstengaged position and have a second disengaged position configured tocreate an open circuit. The thermocouple electrically can be coupled toone of the first and second electrical contacts, wherein the heaterassembly can be configured so that the movable contact member of thepressure switch is in the second disengaged position at a set fluidpressure of fuel in fluid communication with the valve member to createan open circuit with the thermocouple.

According to some embodiments, a heater assembly can comprise a burner,a pressure regulator unit, a pilot nozzle, a temperature sensor, acontrol valve, and a pressure switch. The pressure regulator unit can beconfigured to regulate either a fuel flow of a first fuel type within afirst predetermined range or of a second fuel type within a secondpredetermined range different from the first, the pressure regulatorunit comprising a housing having first and second fuel hook-ups, thefirst fuel hook-up for connecting the first fuel type to the heaterassembly and the second hook-up for connecting the second fuel type tothe heater assembly. The control valve for controlling the flow of saidfirst type of fuel and the flow of said second type of fuel to saidburner. The pressure switch communicating with one of said first andsecond fuel hook-ups, wherein when fuel has a pressure below a thresholdsaid pressure switch permits said temperature sensor to electricallyconnect with said control valve and when a fuel has above said pressurethreshold said pressure switch prevents said temperature sensor fromelectrically connecting with said control valve.

A safety pilot according to some embodiments can comprise a first pilotnozzle having an outlet, a first thermocouple and a second thermocouple.The first and second thermocouples can be spaced from the pilot nozzlesuch that under desired operating conditions, the first thermocouplegenerates a voltage in response to heat from said first pilot nozzle butthe second thermocouple does not. When an incorrect fuel is connected tothe safety pilot, the second thermocouple, or both the first and secondthermocouples, generates voltage in response to heat from said firstpilot nozzle. The current generated from the second thermocouple can beused to indicate an error condition. For example, the current may besent to a control valve or a circuit board to close a valve, and/orinitiate a stop sequence. In some embodiments the signal may interrupt,reduce, or otherwise change a separate signal, such as for example, thecurrent generated by the first thermocouple.

In some embodiments a safety pilot can comprise a first pilot nozzlehaving an outlet, a first thermocouple and a second thermocouple. Thefirst thermocouple can be positioned a first distance from said outletof said first pilot nozzle, said first thermocouple comprising a firstanode and a first cathode and configured to generate voltage in responseto heat from said first pilot nozzle. The second thermocouple can bepositioned a second distance from said outlet of said first pilotnozzle, said second thermocouple comprising a second anode and a secondcathode and configured to generate voltage in response to heat from saidfirst pilot nozzle. The second cathode can be in electrical contact withsaid first anode, said second anode being in electrical contact withsaid first cathode, such that when a single thermocouple is heated inresponse to heat from said first pilot nozzle a first current isgenerated by the safety pilot and when both the first and the secondthermocouples are heated in response to heat from said first pilotnozzle, two currents are generated which combine to generate a secondcurrent that is less than the first current.

According to some embodiments, a heater assembly can comprise a firstpilot nozzle having an outlet, a first thermocouple, a secondthermocouple, and an electrically responsive valve in electricalcommunication with said first thermocouple and said second thermocouple.The first thermocouple can be positioned a first distance from saidoutlet of said first pilot nozzle, said first thermocouple generatingvoltage in response to heat from said first pilot nozzle. The secondthermocouple can be positioned a second distance from said outlet ofsaid first pilot nozzle, said second thermocouple generating voltage inresponse to heat from said first pilot nozzle. The first thermocouplecan be in electrical contact with said second thermocouple. Theelectrically responsive valve can be configured such that (1) said valveis closed when insufficient signal is generated by said firstthermocouple and no significant signal is generated by said secondthermocouple; (2) said valve opens in response to a first signal levelfrom said first thermocouple when no or insufficient signal is generatedby said second thermocouple and (3) said valve closes in response tosaid first signal level from said first thermocouple and a sufficientsignal level from said second thermocouple.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages are described belowwith reference to the drawings, which are intended to illustrate but notto limit the invention. In the drawings, like reference charactersdenote corresponding features consistently throughout similarembodiments.

FIG. 1 is a perspective view of an embodiment of a heating device.

FIG. 2 is a perspective view of an embodiment of a fuel delivery systemcompatible with the heating device of FIG. 1.

FIG. 3 is a perspective cutaway view of a portion of one embodiment of aheater configured to operate using either a first fuel source or asecond fuel source.

FIG. 4 is a partially dissembled perspective view of the heater of FIG.3.

FIGS. 5 and 6 show a pilot assembly in use with a first fuel and asecond fuel respectively.

FIGS. 7 and 8 show a dual fuel pilot assembly in use with a first fueland a second fuel respectively.

FIG. 9 schematically represents an electric circuit between the controlvalve and two thermocouples.

FIG. 10 is a schematic representation of another embodiment of heatingsystem.

FIG. 10A is a schematic representation of another embodiment of heatingsystem.

FIG. 11 is a chart showing typical gas pressures of different fuels.

FIG. 12 shows a cross-sectional view of a pressure switch.

FIG. 13 illustrates a heating unit with a pressure switch.

FIG. 14 shows a heater including the heating unit of FIG. 13.

FIG. 14A shows a schematic detail view of a portion of the heater ofFIG. 14.

FIG. 15 shows a schematic diagram of the function of the heater of FIG.14.

FIG. 16 shows a schematic diagram of the function of another embodimentof heater.

FIGS. 17 and 17A show another embodiment of heating source.

FIG. 18 is a cross-section taken along line C-C of FIG. 17A.

FIG. 19 is a cross-section taken along line B-B of FIG. 17A.

FIG. 20 is the cross-section of FIG. 18 shown with a fitting.

FIG. 21 is the cross-section of FIG. 19 shown with a fitting.

FIG. 22 shows another embodiment of a heating source.

FIG. 23 shows a top view of the heating source of FIG. 22.

FIG. 24A is a cross-section taken along the line 24A-24A of FIG. 23.

FIG. 24B is a cross-section taken along the line 24B-24B of FIG. 23.

FIG. 25A show a perspective view partially in cross-section of anotherembodiment of pressure switch.

FIG. 25B is a side cross-sectional view of the pressure switch of FIG.25A.

FIG. 26 shows a heater.

FIGS. 27A, 28A and 29A show partially dissembled views of the heater ofFIG. 26 illustrating different flow configurations.

FIGS. 27B, 28B and 29B respectively show a schematic diagram of the flowconfiguration of one of FIGS. 27A, 28A and 29A.

FIGS. 30 and 31 show perspective views of another embodiment of heatingsource.

FIG. 32 is a side view of the heating source of FIG. 30 in partialcross-section.

FIG. 32A is a detail view of the heating source from circle A in FIG.32.

FIG. 33 is a side view of the heating source of FIG. 30.

FIG. 33A is a top view of the heating source with a partialcross-section taken along line B-B of FIG. 33.

FIG. 33B is a detail view of the heating source from the partialcross-section of FIG. 33A.

DETAILED DESCRIPTION

Many varieties of appliances, such as heaters, boilers, dryers, washingmachines, ovens, fireplaces, stoves, and other heat-producing devicesutilize pressurized, combustible fuels. For example, many varieties ofspace heaters, fireplaces, stoves, ovens, boilers, fireplace inserts,gas logs, and other heat-producing devices employ combustible fuels,such as liquid propane and/or natural gas. These devices generally aredesigned to operate with a single fuel type at a specific pressure. Forexample, as one having skill in the art would appreciate, some gasheaters that are configured to be installed on a wall or a floor operatewith natural gas at a pressure in a range from about 3 inches of watercolumn to about 6 inches of water column, while others operate withliquid propane at a pressure in a range from about 8 inches of watercolumn to about 12 inches of water column.

Although certain embodiments discussed herein are described in thecontext of directly vented heating units, such as fireplaces andfireplace inserts, or vent-free heating systems, it should be understoodthat certain features, principles, and/or advantages described areapplicable in a much wider variety of contexts, including, for example,gas logs, heaters, heating stoves, cooking stoves, barbecue grills,water heaters, and any flame-producing and/or heat-producingfluid-fueled unit, including without limitation units that include aburner of any suitable variety.

FIG. 1 illustrates an embodiment of a fireplace, fireplace insert,heat-generating unit, or heating device 10 configured to operate with asource of combustible fuel. In various embodiments, the heating device10 is configured to be installed within a suitable cavity, such as thefirebox of a fireplace or a dedicated outer casing. The heating device10 can extend through a wall, in some embodiments.

The heating device 10 includes a housing 20. The housing 20 can includemetal or some other suitable material for providing structure to theheating device 10 without melting or otherwise deforming in a heatedenvironment. The housing 20 can define a window 220. In someembodiments, the window 220 comprises a sheet of substantially clearmaterial, such as tempered glass, that is substantially impervious toheated air but substantially transmissive to radiant energy.

The heating device 10 can include a sealed chamber 14. The sealedchamber 14 can be sealed to the outside with the exception of the airintake 240 and the exhaust 260. Heated air does not flow from the sealedchamber to the surroundings; instead air, for example from in aninterior room, can enter an inlet vent into the housing 20. The air canpass through the housing in a channel passing over the outside of thesealed chamber 14 and over the exhaust 260. Heat can be transferred tothe air which can then pass into the interior room through an outletvent.

In some embodiments, the heating device 10 includes a grill, rack, orgrate 280. The grate 280 can provide a surface against which artificiallogs may rest, and can resemble similar structures used in wood-burningfireplaces. In certain embodiments, the housing 20 defines one or moremounting flanges 300 used to secure the heating device 10 to a floorand/or one or more walls. The mounting flanges 300 can include apertures320 through which mounting hardware can be advanced. Accordingly, insome embodiments, the housing 20 can be installed in a relatively fixedfashion within a building or other structure.

As shown, the heating device 10 includes a fuel delivery system 40,which can have portions for accepting fuel from a fuel source, fordirecting flow of fuel within the heating device 10, and for combustingfuel. In the illustrated embodiment, portions of an embodiment of thefuel delivery system 40 that would be obscured by the heating device 10are shown in phantom. Specifically, the illustrated heating device 10includes a floor 50 which forms the bottom of the sealed combustionchamber 14 and the components shown in phantom are positioned beneaththe floor 50.

With reference to FIG. 2, an example of a fuel delivery system 40 isshown. The fuel delivery system 40 can include a regulator 120. Theregulator 120 can be configured to selectively receive a fluid fuel(e.g., propane or natural gas) from a source at a certain pressure. Incertain embodiments, the regulator 120 includes an input port 121 forreceiving the fuel. The regulator 120 can define an output port 123through which fuel exits the regulator 120. Accordingly, in manyembodiments, the regulator 120 is configured to operate in a state inwhich fuel is received via the input port 121 and delivered to theoutput port 123. In certain embodiments, the regulator 120 is configuredto regulate fuel entering the port 121 such that fuel exiting the outputport 123 is at a relatively steady pressure. The regulator 120 canfunction in ways similar to the pressure regulators disclosed in U.S.patent application Ser. No. 11/443,484, filed May 30, 2006, now U.S.Pat. No. 7,607,426, the entire contents of which are hereby incorporatedby reference herein and made a part of this specification.

The output port 123 of the regulator 120 can be coupled with a sourceline or channel 125. The source line 125, and any other fluid linedescribed herein, can comprise piping, tubing, conduit, or any othersuitable structure adapted to direct or channel fuel along a flow path.In some embodiments, the source line 125 is coupled with the output port123 at one end and is coupled with a control valve 130 at another end.The source line 125 can thus provide fluid communication between theregulator 120 and the control valve 130.

The control valve 130 can be configured to regulate the amount of fueldelivered to portions of the fuel delivery system 40. Variousconfigurations of the control valve 130 are possible, including thoseknown in the art as well as those yet to be devised. In someembodiments, the control valve 130 includes a millivolt valve. Thecontrol valve 130 can comprise a first knob or dial 131 and a seconddial 132. In some embodiments, the first dial 131 can be rotated toadjust the amount of fuel delivered to a burner 190, and the second dial132 can be rotated to adjust a setting of a thermostat. In otherembodiments, the control valve 130 comprises a single dial 131.

In many embodiments, the control valve 130 is coupled with a burnertransport line or channel 124 and a pilot transport or delivery line126. The burner transport line 124 can be coupled with a nozzle assembly160 which can be further coupled with a burner delivery line 148. Thenozzle assembly 160 can be configured to direct fuel received from theburner transport line 132 to the burner delivery line or channel 148.

The pilot delivery line 126 is coupled with a pilot 180. Fuel deliveredto the pilot 180 can be combusted to form a pilot flame, which can serveto ignite fuel delivered to the burner 190 and/or serve as a safetycontrol feedback mechanism that can cause the control valve 130 to shutoff delivery of fuel to the fuel delivery system 40. Additionally, insome embodiments, the pilot 180 is configured to provide power to thecontrol valve 130. Accordingly, in some embodiments, the pilot 180 iscoupled with the control valve 130 by one or more of a feedback line 182and a power line 183.

The pilot 180 can comprise an igniter or an electrode configured toignite fuel delivered to the pilot 180 via the pilot delivery line 126.Accordingly, the pilot 180 can be coupled with an igniter line 184,which can be connected to an igniter actuator, button, or switch 186. Insome embodiments, the igniter switch 186 is mounted to the control valve130. In other embodiments, the igniter switch 186 is mounted to thehousing 20 of the heating device 10. The pilot 180 can also comprise athermocouple. Any of the lines 182, 183, 184 can comprise any suitablemedium for communicating an electrical quantity, such as a voltage or anelectrical current. For example, in some embodiments, one or more of thelines 182, 183, 184 comprise a metal wire.

Furthermore, as discussed below, when a pilot light heats thethermocouple a current is generated in the thermocouple. In certainembodiments, this current produces a magnetic field within the controlvalve 130 that maintains the valve 130 in an open position. If the pilotlight goes out or is disturbed, and the current flow is reduced orterminated, the magnetic field weakens or is eliminated, and the valve130 closes, thereby preventing passage of fuel.

The pilot 180 may also be an oxygen depletion sensor (ODS) 180. Invarious embodiments, the ODS 180 provides a steady pilot flame thatheats the thermocouple unless the oxygen level in the ambient air dropsbelow a threshold level. In certain embodiments, the threshold oxygenlevel is between about 18 percent and about 18.5 percent. In someembodiments, when the oxygen level drops below the threshold level, thepilot flame moves away from the thermocouple, the thermocouple cools,and the heat control valve 130 closes, thereby cutting off the fuelsupply to the heater 10. It will be understood that most all referencesto pilot and pilot assembly also refer to an ODS.

The burner delivery line 148 is situated to receive fuel from the nozzleassembly 160, and can be connected to the burner 190. The burner 190 cancomprise any suitable burner, such as, for example, a ceramic tileburner or a blue flame burner, and is preferably configured tocontinuously combust fuel delivered via the burner delivery line 148.

The flow of fuel through the fuel delivery system 40, as shown, will nowbe described. A fuel is introduced into the fuel delivery system 40through the regulator 120 which then proceeds from the regulator 120through the source line or channel 125 to the control valve 130. Thecontrol valve 130 can permit a portion of the fuel to flow into theburner transport line or channel 132, and can permit another portion ofthe fuel to flow into the pilot transport line or channel 126. The fuelflow in the burner transport line 132 can proceed to the nozzle assembly160. The nozzle assembly 160 can direct fuel from the burner transportline or channel 132 into the burner delivery line or channel 148. Insome embodiments, fuel flows through the pilot delivery line or channel126 to the pilot 180, where it is combusted. In some embodiments, fuelflows through the burner delivery line or channel 148 to the burner 190,where it is combusted.

An air shutter 150 can also be along the burner delivery line 148. Theair shutter 150 can be used to introduce air into the flow of fuel priorto combustion at the burner 190. This can create a mixing chamber 157where air and fuel is mixed together prior to passing through the burnerdelivery line 148 to the burner 190. The amount of air that is needed tobe introduced can depend on the type of fuel used. For example, propanegas at typical pressures needs more air than natural gas to produce aflame of the same size.

The air shutter 150 can be adjusted by increasing or decreasing the sizeof a window 155. The window 155 can be configured to allow air to passinto and mix with fuel in the burner delivery line 148.

FIGS. 3 and 4 show an embodiment of a dual fuel heater 100. The heatercan be made for use with two different fuels, where in a first settingthe heater is set to use the first fuel and in a second setting theheater is set to use the second fuel. The heater 100 can be configuredsuch that the installer of the gas appliance can connect the assembly toone of two fuels, such as either a supply of natural gas (NG) or asupply of propane (LP) and the assembly will desirably operate in thestandard mode (with respect to efficiency and flame size and color) foreither gas. The heater 100 can be, for example, a vent-free infraredheater or a vent-free blue flame heater. Other configurations are alsopossible for the heater 100.

Though the heater 100 is configured for dual fuel use, the heater caninclude many of the same types of components as the heater 10 as will beunderstood by review of the below description. It will be understoodthat like reference characters or terminology denote correspondingfeatures, but this does not require that the components be identical inall aspects.

The heater 100 can comprise a housing 200. In the illustratedembodiment, the housing 200 comprises a window 220, one or more intakevents 240 and one or more outlet vents 260. Heated air and/or radiantenergy can pass through the window 220. Air can flow into the heater 100through the one or more intake vents 240 and heated air can flow out ofthe heater 100 through the outlet vents 260.

With reference to FIG. 4, in certain embodiments, the heater 100includes a regulator 120. The regulator 120 can be coupled with sourceline 125. The source line 125 can be coupled with a heater control valve130, which, in some embodiments, includes a knob 132. As illustrated,the heater control valve 130 is coupled to a fuel supply pipe 124 and anoxygen depletion sensor (ODS) pipe 126, each of which can be coupledwith a fluid flow controller 140. The fluid flow controller 140 can becoupled with a first nozzle line 141, a second nozzle line 142, a firstODS line 143, and a second ODS line 144. In some embodiments, the firstand the second nozzle lines 141, 142 are coupled with a nozzle 160, andthe first and the second ODS lines 143, 144 are coupled with an ODS 180.In some embodiments, the ODS comprises a thermocouple 182, which can becoupled with the heater control valve 130, and an igniter line 184,which can be coupled with an igniter switch 186. Each of the pipes 125,124, and 126 and the lines 141-144 can define a fluid passageway or flowchannel through which a fluid can move or flow.

In some embodiments, including the illustrated embodiment, the heater100 comprises a burner 190. The ODS 180 can be mounted to the burner190, as shown. The nozzle 160 can be positioned to discharge a fluid,which may be a gas, liquid, or combination thereof into the burner 190.For purposes of brevity, recitation of the term “gas or liquid”hereafter shall also include the possibility of a combination of a gasand a liquid. In addition, as used herein, the term “fluid” is a broadterm used in its ordinary sense, and includes materials or substancescapable of fluid flow, such as gases, liquids, and combinations thereof.

Where the heater 100 is a dual fuel heater, either a first or a secondfluid is introduced into the heater 100 through the regulator 120. Stillreferring to FIG. 4, the first or the second fluid proceeds from theregulator 120 through the source line 125 to the heater control valve130. The heater control valve 130 can permit a portion of the first orthe second fluid to flow into the fuel supply pipe 124 and permitanother portion of the first or the second fluid to flow into the ODSpipe 126. From the heater control valve 130, the first or the secondfluid can proceed to the fluid flow controller 140. In many embodiments,the fluid flow controller 140 is configured to channel the respectiveportions of the first fluid from the fuel supply pipe 124 to the firstnozzle line 141 and from the ODS pipe 126 to the first ODS line 143 whenthe fluid flow controller 140 is in a first state, and is configured tochannel the respective portions of the second fluid from the fuel supplypipe 124 to the second nozzle line 142 and from the ODS pipe 126 to thesecond ODS line 144 when the fluid flow controller 140 is in a secondstate.

In certain embodiments, when the fluid flow controller 140 is in thefirst state, a portion of the first fluid proceeds through the firstnozzle line 141, through the nozzle 160 and is delivered to the burner190, and a portion of the first fluid proceeds through the first ODSline 143 to the ODS 180. Similarly, when the fluid flow controller 140is in the second state, a portion of the second fluid proceeds throughthe nozzle 160 and another portion proceeds to the ODS 180. Otherconfigurations are also possible. The heater 100 and components thereofcan be further understood with reference to U.S. patent application Ser.No. 11/443,484, filed May 30, 2006, now U.S. Pat. No. 7,607,426, theentire contents of which are hereby incorporated by reference herein andmade a part of this specification.

With reference now to FIGS. 5-6, a pilot assembly 180 will now bediscussed. The pilot assembly 180 can be used in conjunction with eitherof the heaters 10, 100 discussed above, as well as, with otherembodiments of heating devices. Fuel delivered to the pilot 180 can becombusted to form a pilot light or flame 800. When the pilot light 800heats the thermocouple 182 a current is generated in the thermocouple.This current is used in some heaters to generate a magnetic field withinthe control valve 130 to maintain the valve 130 in an open position.

In operation, the pilot assembly generally first needs to be provedbefore fuel can flow to the burner nozzle 160 and then on to the burner190. Proving the pilot is generally the initial step in turning on theheater. As has been discussed, the pilot 180 has a thermocouple 182 thatgenerates an electric current when heated to hold open the control valve130. If the thermocouple is not hot enough there won't be enough currentgenerated to keep the control valve open. Generally speaking, when thecontrol valve is in a pilot position, the control valve is also beingheld in an open position to allow flow to the pilot 180, but not to theburner nozzle 160. When the control valve is moved from the pilotposition to a heating position, the control valve is no longer held openbut requires the electric current from the thermocouple to hold thevalve open. Thus, if there is not yet enough heat and the control valvewere adjusted from the pilot position to the heating position, i.e. byturning the knob 132, the control valve will close and fuel will not beable to flow to the burner. And in fact, most control valves will notallow the user to rotate the knob, or change the position of the controlto a heating condition, until after the pilot has been proven.

Once lit, if the pilot light 800 goes out or is disturbed, and thecurrent flow is reduced or terminated, the magnetic field weakens or iseliminated, and the valve 130 closes, thereby preventing further flow offuel. So with the control valve in a heating position, the pilot ensuresthat if the flame goes out, uncombusted fuel will not continue to flowinto the room or space where the heating assembly is located. In thisway the pilot can prevent a potential safety hazard, such as anexplosion.

If the pilot assembly is also an oxygen depletion sensor (ODS) 180, thenthe ODS can cause the control valve 130 to close when the oxygen leveldrops below a certain threshold. For example, the threshold oxygen levelcan be between about 18 percent and about 18.5 percent. As the oxygenlevel changes the pilot light 800 moves with respect to the thermocouple182. When the oxygen level drops below the threshold level, the pilotflame 800 moves away from the thermocouple 182, the thermocouple 182cools, and the control valve 130 closes, thereby cutting off the fuelsupply to the heater 10, 100.

The illustrated pilot assembly 180 can also be used to shut off flowthrough the control valve 130 when an excessive heat threshold or othercondition is met. For example, if the wrong fuel is connected to theheater 10, 100 depending on the fuel, a large flame 800B such as thatshown in FIG. 6 may be produced. It will be understood that this wrongfuel could also provide an undesirably large flame at the burner 190creating a potential safety hazard.

The pilot assembly 180 can be configured to prevent the heater 10, 100from starting if the wrong fuel is connected to the heater, or if anexcessive temperature condition is experienced at the pilot 180. In someembodiments, a temperature sensor, such as second thermocouple 810 canbe used to detect an excessive temperature condition and/or theconnection of the wrong fuel. A signal can be sent to the control valve130 or to a printed circuit board, or the signal from the firstthermocouple 182 can be interrupted, to thereby close the control valveor to activate some other shut off feature. In some embodiments, thiscan be done before fuel is permitted to flow to the burner nozzle 160,or before the pilot has been fully proven. For example, the heatingassembly can be configured to detect an undesired condition while thepilot is being proven and before the fuel can flow to the burner nozzle160. This can beneficially prevent a potential safety hazard.

As one example, if the heater is a natural gas heater the pilot assemblycan be configured for use with natural gas. The pilot flame 800A shownin FIG. 5 can represent the normal flame size when the pilot assembly isused with natural gas. As can be seen, the thermocouple 182 is not onlyadjacent the flame 800A but is actually within and surrounded by it. Inthis condition, the flame 800A would heat thermocouple 182 to generatean electric current to hold open the control valve 130. But, it can alsobe seen that the flame 800A is spaced away from the second thermocouple810. In this condition the flame 800A would not provide sufficientheating to the second thermocouple to exceed the set threshold.

Thus, in this condition, the first thermocouple 182 can be heatedsufficiently to prove the pilot, thereafter allowing flow to the burnernozzle when the heater is changed from the pilot position to a heatingposition. But the second thermocouple is not heated sufficient togenerate a closing signal to the control valve, or to interrupt thecurrent from the first thermocouple 182. The first thermocouple can bespaced a first distance from the nozzle. The second thermocouple can bespaced a second distance from the nozzle. Preferably, the seconddistance is greater than the first distance, but in some embodiments thedistances may be the same, of the second distance may be less than thefirst distance.

In FIG. 6 it can be seen that large flame 800B contacts and surroundsboth the first and second thermocouples 182, 810. Where the pilotassembly 180 is configured for use with natural gas, this can be thecondition when liquid propane is passed into the pilot assembly. Thesensed temperature at the second thermocouple can exceed the setthreshold to cause the control valve to close as will be described inmore detail below.

As shown, the pilot assembly 180 comprises a first thermocouple 182, anozzle 801, and an electrode 808, and a second thermocouple 810. It willbe understood that other temperature sensors and devices could be usedinstead of, or in addition to, one or both of the thermocouples, such asa thermopile. The pilot assembly 180 can include a frame 820 forpositioning the constituent parts of the pilot assembly. The nozzle 801can include an injector 811 to be coupled with the line 143 (see FIGS.1-4), an air inlet 821, and an outlet 803.

In many embodiments, the injector is a standard injector as are known inthe art, such as an injector that can be utilized with liquid propane ornatural gas. Thus, the injector can have an internal orifice sized for aparticular fuel. The nozzle 801 is directed towards the electrode 808 toignite the fuel and towards the thermocouple 182 such that a stableflame 800A exiting the nozzle 801 will heat the thermocouple 182.

A gas or a liquid can flow from the line 143 through the injector 811 tothe outlet 803 and toward the thermocouple 182. The fluid flows near theair inlet 821 drawing in air for mixing with the fluid. In someembodiments, a user can activate the electrode by depressing the igniterswitch 186 (see FIGS. 2 and 4). The electrode can comprise any suitabledevice for creating a spark to ignite a combustible fuel. In someembodiments, the electrode is a piezoelectric igniter.

With reference now to FIGS. 7-8, a dual fuel pilot assembly 180′ will bediscussed. As previously mentioned, the pilot assembly 180′ can also bean oxygen depletion sensor. The pilot assembly 180′ can function is amanner substantially similar to the pilot assembly 180. The primarydifference being that the dual fuel pilot assembly 180′ has a secondnozzle 802. The first nozzle 801 can be configured for use with a firstfuel, such as natural gas, and the second nozzle 802 can be configuredfor use with a second fuel, such as liquid propane. As shown, the pilotassembly 180′ also includes a second electrode 809. It will beunderstood that some embodiments may only have a single electrode.

Similar to the first nozzle, the second nozzle can include an injector812, an air inlet 822, and an outlet 804. In some embodiments, the firstnozzle 801 and the second nozzle 802 are directed toward thethermocouple such that a stable flame exiting either of the nozzles 801,802 will heat the thermocouple 182. In certain embodiments, the firstnozzle 801 and the second nozzle 802 are directed to different sides ofthe thermocouple 182. In some embodiments, the first nozzle 801 and thesecond nozzle 802 are directed to opposite sides of the thermocouple182. In some embodiments, the first nozzle 801 is spaced closer to thethermocouple than is the second nozzle 802.

In some embodiments, the first nozzle 801 comprises a first air inlet821 at a base thereof and the second nozzle 802 comprises a second airinlet 822 at a base thereof. In various embodiments, the first air inlet821 is larger or smaller than the second air inlet 822. In manyembodiments, the first and second injectors 811, 812 are also located ata base of the nozzles 801, 802. In certain embodiments, a gas or aliquid flows from the first line 143 through the first injector 811,through the first nozzle 801, and toward the thermocouple 182. In otherembodiments, a gas or a liquid flows from the second line 144 throughthe second injector 812, through the second nozzle 802, and toward thethermocouple 182. In either case, the fluid flows near the first orsecond air inlets 821, 822, thus drawing in air for mixing with thefluid. In certain embodiments, the first injector 811 introduces a fluidinto the first nozzle 801 at a first flow rate, and the second injector812 introduces a fluid into the second nozzle 802 at a second flow rate.In various embodiments, the first flow rate is greater than or less thanthe second flow rate.

In some embodiments, the first electrode 808 is positioned at anapproximately equal distance from an output end of the first nozzle 801and an output end of the second nozzle 802. In some embodiments, asingle electrode is used to ignite fuel exiting either the first nozzle801 or the second nozzle 802. In other embodiments, a first electrode808 is positioned closer to the first nozzle 801 than to the secondnozzle 802 and the second electrode 809 is positioned nearer to thesecond nozzle 802 than to the first nozzle 801.

With reference back to any of FIGS. 5-8, certain embodiments of anelectrical control system will be described. As shown in FIGS. 5-8 thethermocouples are electrically connected. Wires 813 and 815 areconnected to the first thermocouple 182 and wires 817 and 819 areconnected to the second thermocouple. The wires 813 and 817 representthe positive wire connected to the anode of the thermocouple and wires815 and 819 represent the negative wire connected to the cathode of thethermocouple. It can be seen that the second thermocouple iselectrically connected to the first thermocouple with opposite wires orin reverse polarity. In other words, the positive wire 813 of the firstthermocouple 182 is connected to the negative wire 819 of the secondthermocouple 810. Also the negative wire 815 of the first thermocouple182 is connected to the positive wire 817 of the second thermocouple810. In this way, when the second thermocouple is heated, the currentfrom the first thermocouple can be effectively cancelled out orinterrupted by generating a current that flows in the oppositedirection. Thus, when the wrong fuel is connected to the heater, or tothe wrong connection of the heater, the second thermocouple can detectthe excessive temperature and prevent the pilot from proving.

In some embodiments, a pilot can comprise a first thermocouple, a secondthermocouple and a nozzle pointing at both thermocouples. The pilot canbe configured to direct a flame at only the first thermocouple duringnormal operation and at both thermocouples when an incorrect fuel isdirected through the pilot. In some embodiments, the thermocouples canbe electrically connected in reverse polarity. In some embodiments, thepilot can include a second nozzle. The second nozzle can be pointed atonly the first thermocouple. In other embodiments, the second nozzle canbe pointed at a third thermocouple and the position of the second nozzleand third thermocouple can be independent from the position of the othernozzle and thermocouples.

Looking now to FIG. 9, a schematic diagram is shown of the control valve130 and the two thermocouples 182 and 810. The illustrated control valve130 includes a solenoid that can hold the valve in an open position whenan electric current is generated by the first thermocouple 182.

The first thermocouple can generate an electric potential E1 and has aninternal resistance r1. The second thermocouple can generate an electricpotential E2 and has an internal resistance r2. The solenoid has aninternal resistance R. In the illustrated embodiment, when the correctgas is connected to the heating system, only the first thermocouplegenerates an electric potential E1. Thus the current I generated equals:

I=E1(r1+r2)/(R(r1+r2)+r1r2)  (1)

And when the wrong gas is connected such that a larger flame 800B isgenerated, the current I equals:

I=((E1−E2)(r1+r2))/(R(r1+r2)+r1r2)  (2)

The second thermocouple generates a reverse potential which can causethe potential to drop. This will reduce the current and in someembodiments may effectively cancel out the potential from the firstthermocouple. The solenoid needs a rated current to operate, but as thesecond thermocouple causes a potential drop the solenoid can close. Thiscan prevent a potential safety issue and/or the wrong fuel from flowingthrough the system.

A thermocouple can include one or more an anode and a cathode. The anodecan be the negative terminal on the thermocouple and the cathode can bethe positive terminal.

A safety pilot can comprise a first pilot nozzle having an outlet, afirst thermocouple and a second thermocouple. The first thermocouple canbe positioned a first distance from said outlet of said first pilotnozzle, said first thermocouple comprising a first anode and a firstcathode and configured to generate voltage in response to heat from saidfirst pilot nozzle. The second thermocouple can be positioned a seconddistance from said outlet of said first pilot nozzle, said secondthermocouple comprising a second anode and a second cathode andconfigured to generate voltage in response to heat from said first pilotnozzle.

In some embodiments, the thermocouples can be electrically connected inreverse polarity. The second cathode can be in electrical contact withthe first anode, and the second anode can be in electrical contact withthe first cathode. In some embodiments, a wire leading from the positiveterminal of the first thermocouple can be connected to the negativeterminal of the second thermocouple. And a wire leading from thenegative terminal of the first thermocouple can be connected to thepositive terminal of the second thermocouple. A single set of wires maythen be used to connect the pilot to a control valve or otherelectrically responsive valve.

With the thermocouples electrically connected in reverse polarity andwhen heated by the pilot, two separate currents can be generated whichcan have the effect of reducing the generated current and/or effectivelycancelling each other out as has been explained above. But, when onlyone thermocouple is heated by the pilot, a usable current can begenerated.

In some embodiments, the cathode of the first thermocouple is inelectrical contact with the anode of the second thermocouple and theanode of the first thermocouple is in electrical contact with thecathode of the second thermocouple. Thus, when a single thermocouple isheated in response to heat from said the pilot nozzle a first current isgenerated by the safety pilot and when both the first and the secondthermocouples are heated in response to heat from the pilot nozzle, twocurrents are generated which combine to generate a second current thatis less than the first current.

A heating assembly can include a pilot and an electrically responsivevalve in electrical communication with a first thermocouple and a secondthermocouple of the pilot. The electrically responsive valve can directfuel flow to a burner through a burner nozzle. (1) The valve canmaintain a closed position when an insufficient signal is generated bythe first thermocouple and no significant signal is generated by thesecond thermocouple. (2) The valve can maintain an open position inresponse to a first signal level from said first thermocouple when no orinsufficient signal is generated by said second thermocouple. (3) Thevalve can close in response to the first signal level from the firstthermocouple and a sufficient signal level from the second thermocoupleor from simply a sufficient signal level from the second thermocouple.If the electrically responsive valve is a control valve that directsfuel to both the burner and the pilot, it will be understood, that theelectrically responsive valve may also direct fuel to the pilot lightapart from the actions of the valve controlling the flow of fuel to theburner and the burner nozzle.

Many different types of temperature sensors can be used to detect anexcessive temperature condition and/or the connection of the wrong fuel.For example, in many embodiments a thermopile could be used in place ofone or more of the thermocouples discussed herein. The signal generatedcould be sent to the control valve 130, but could also be sent to aprinted circuit board. In addition, one or more shut off features can beincluded in the system instead of, or in addition to the control valve.

FIG. 10 is a schematic representation of another embodiment of heatingsystem. In the illustrated heating system basic components of theheating system are shown including a regulator 120, a control valve 130,a nozzle assembly 160, a burner 190, and a pilot assembly 180. Theheating system and components can function in a similar manner to thosepreviously described and can be a single fuel or a dual fuel system.Thus, for example fuel can flow from the regulator 120 to the controlvalve. The control valve 130 can provide fuel to both the nozzleassembly 160 and to the pilot assembly 180. The nozzle assembly 160 candirect fuel to the burner.

The heating system of FIG. 10 also includes a safety feature to preventthe heating system from starting if the wrong fuel is connected to theheating system under certain circumstances. In some embodiments, apressure sensor 60 can be used to detect an incorrect fluid pressureentering the system. The incorrect fluid pressure can be indicative of awrong type of fuel connected to the heating system. In some embodiments,a signal from the pressure switch 60 can be sent to the control valve130, or the signal from the thermocouple 182 can be interrupted, tothereby close the control valve. In some embodiments, this can be donebefore fuel is permitted to flow to the burner nozzle 160, or before thepilot has been fully proven. For example, the heating assembly can beconfigured to detect an undesired condition while the pilot is beingproven and before the fuel can flow to the burner nozzle 160. This canbeneficially prevent a potential safety hazard.

Different fuels are generally run at different pressures. FIG. 11 showsfour different fuels: methane, city gas, natural gas and liquid propane;and a typical pressure range of each particular fuel. The typicalpressure range can mean the typical pressure range of the fuel asprovided by a container, a gas main, a gas pipe, etc. for consumer use,such as the gas provided to an appliance. Thus, natural gas is generallyprovided to a home gas oven within the range of 4 to 7 inches of watercolumn. The natural gas can be provided to the oven through pipingconnected to a gas main. As another example, propane may be provided toa barbeque grill from a propane tank with the range of 10 to 14 inchesof water column. The delivery pressure of any fuel may be furtherregulated to provide a more certain pressure range or may beunregulated. For example, the barbeque grill may have a pressureregulator so that the fuel is delivered to the burner within the rangeof 10 to 12 inches of water column rather than within the range of 10 to14 inches of water column.

As shown in the chart, city gas can be a combination of one or moredifferent gases. As an example, city gas can be the gas typicallyprovided to houses and apartments in China, and certain other countries.At times, and from certain sources, the combination of gases in city gascan be different at any one given instant as compared to the next.

Because each fuel has a typical range of pressures that it is deliveredat, these ranges can advantageously be used in a heating assembly toensure that the proper gas is connected to the proper inlet. Inparticular, a pressure sensor can be used to determine the pressure ofthe gas before, or as it enters the regulator. If the pressure is notwithin the typical range or is greatly outside of the typical range ofthe desired fuel, the control valve can be triggered to close,preventing the incorrect fuel from flowing to the burner nozzle 160 andto the burner 190. In some embodiments, the pressure sensor could be setto a threshold pressure level above the typical pressure range, forexample, about 0.5, 1, 1.5 or 2 inches of water column above or belowthe typical pressure range. In a preferred embodiment, the pressuresensor is set at a threshold level above the typical pressure range.

One embodiment of such a system is represented in FIG. 10. A pressureswitch 60 can be fluidly connected to an inlet on or in fluidcommunication with the pressure regulator 120. The pressure switch 60can be electrically connected to one or more of the control valve 130,the pilot assembly 180, and the igniter. As shown, the pressure switch60 is electrically connected to both the control valve 130 and the pilotassembly 180. The pressure switch 60 can be a normally closed switch andcan be electrically positioned between the thermocouple 182 and thecontrol valve 180. Thus, if the pressure switch is opened the circuitbetween the thermocouple and the control valve will be opened andcurrent from the thermocouple will be prevented from reaching thecontrol valve as the circuit will be an open circuit. Otherconfigurations of the system can also be used.

In another embodiment as shown in FIG. 10A, the pressure switch 60 canbe electrically connected to the igniter 808. The pressure switch 60 canbe a normally closed switch and can be electrically positioned betweenthe switch 186 for the igniter and the igniter 808 itself, such as apiezoelectric igniter. Thus, if the pressure switch is opened thecircuit between the igniter switch and the igniter will be opened andcurrent from the igniter switch will be prevented from reaching theigniter as the circuit will be an open circuit. Thus, if the pressure istoo high, which may indicate the wrong fuel is connected to the heater,the pilot assembly 180 cannot be ignited with the igniter 808.

In some embodiment, two pressure switches can be used per inlet. Onepressure switch can be set at a low level below the typical pressurerange for the desired fuel and the other can be set at a high levelabove the typical pressure range for the desired fuel. The pressureregulator can be set based on the desired fuel. Thus, if the heatingassembly is a dual fuel heating assembly, the heating assembly may havetwo inlets and four pressure switches, two on each inlet. Similarly, ifthe heating assembly is a single fuel heating assembly, the heatingassembly may have one inlet and one or two pressure switches. In anotherembodiment, the heating assembly can be a dual fuel heating assemblywith a single inlet and it may include one or more pressure switches.

In another embodiment, a dual fuel heating assembly can have two inletsand only one pressure switch. The pressure switch can be connected tothe inlet for the lower pressure fuel and can be set at a level abovethe typical pressure range for that fuel. In this way, the heatingassembly can prevent the higher pressure fuel from being connected tothe inlet for the lower pressure fuel. As an example, the pressureswitch 60 can be used with a natural gas inlet and set to 7.5 inches ofwater column. The second inlet can be used with liquid propane which isdelivered at a higher pressure than natural gas. Propane would alsoproduce a higher flame if introduced through into the system that hasbeen set for natural gas. Thus, the pressure switch can beneficiallyprevent a safety hazard from occurring.

FIG. 12 shows a cross-sectional view of one embodiment of a pressureswitch 60. The pressure switch 60 has a housing 62 having an inlet 68 toreceive fluid as indicated by the arrow and to be able to respond tocertain pressures. As shown, the pressure switch 60 is a normally closedpressure switch. The pressure switch 60 can be set to open when agreater than desired pressure encounters a valve member 58, such as theillustrated diaphragm 58. A spring 64 and screw 66 can be used to setand adjust the pressure required to move the diaphragm 58. A cap 72 cancover the screw 66. In addition, a contact member 56 can move with thediaphragm. The contact member 56 can contact two electrical connectionmembers 52, 54 which can be electrically connected to a printed circuitboard, the igniter 808, igniter switch 186, the control valve 130 and/orthe thermocouple 182, among other features.

As has been discussed previously, under normal operation a flame at thepilot 180 heats the thermocouple 182 to generate a current to maintainthe control valve in an open position. The pressure switch 60 can be setto open this circuit and prevent the current from reaching the controlvalve when the switch 60 has been advanced, if it is a normally closedpressure switch. In another embodiment, the pressure switch 60 can benormally open switch so that the switch will only be closed when aminimum pressure is present at the inlet. The system can operate in asimilar manner with an igniter, a printed circuit board, or with otherfeatures of the heater assembly.

The pressure switch 60 positioned at the inlet can allow the system toprovide a safety check before the pilot has been proven and before fuelbegins to follow to the burner nozzle 160 and the burner 190. As thepressure switch can respond immediately based on the delivery pressureof the fuel.

In some embodiments, a pressure switch is configured such that if a fuelis connected to the first gas hook-up that has a delivery pressureeither above or below a predetermined threshold pressure, the fuel willact on the pressure switch to move a movable contact member from one ofa first or second position to the other position. This will open orclose a circuit as the case may be, such that the pilot light cannot beproven to thereby prevent fuel from flowing to the burner.

A pilot light may comprise a thermocouple electrically coupled to one ofa first and a second electrical contact of the pressure switch and tothe control valve. The heater assembly can be configured so that themovable contact member of the pressure switch is in the seconddisengaged position when the delivery pressure is above thepredetermined threshold pressure to create an open circuit between thethermocouple and the control valve such that the control valve cannotflow fuel to the burner.

In some embodiments, an igniter may be electrically coupled to one ofthe first and second electrical contacts. The heater assembly can beconfigured so that the movable contact member of the pressure switch isin the second disengaged position when the delivery pressure is abovethe predetermined threshold pressure to create an open circuit betweenthe igniter and one of the first and second electrical contacts suchthat the fuel cannot be ignited.

In some embodiments, a pressure switch can communicate with a fuelhook-up. When the fuel has a pressure below a threshold pressure, thepressure switch can permit a temperature sensor to electrically connectwith a control valve. When the fuel is above the threshold pressure, thepressure switch can prevent the temperature sensor from electricallyconnecting with the control valve.

A pressure switch can comprise a housing having an inlet and defining aninternal chamber. The pressure switch can also include a spring, adiaphragm, first and second electrical contacts, and a movable contactmember. The diaphragm can be connected to the spring and positionedwithin the internal chamber such that fluid entering the inlet acts onthe diaphragm. The movable contact member can be connected to thediaphragm such that movement of the diaphragm can cause the movablecontact member to movably engage and disengage the first and secondelectrical contacts, the diaphragm and spring configured to the movablecontact member between engaged and disengaged positions at a set fluidpressure. In some embodiments, the movable contact member is biased tothe engaged position.

Some embodiments of heater assembly can comprise a thermocouple and apressure switch. The pressure switch can comprise a valve member movableat a predetermined threshold pressure, first and second electricalcontacts, and a movable contact member. The movable contact member canbe mechanically connected to the valve member and movable therewith. Themovable contact member can be configured for electrical connection tothe first and second electrical contacts when in a first engagedposition and have a second disengaged position configured to create anopen circuit. The thermocouple can be electrically coupled to one of thefirst and second electrical contacts, wherein the heater assembly isconfigured so that the movable contact member of the pressure switch isin the second disengaged position at a set fluid pressure of fuel influid communication with the valve member to create an open circuit withthe thermocouple.

Turning now to FIG. 13, a heating unit 70 including a pressure switch 60is shown. The heating unit 70 combines certain features of a pressureregulator 120 and a fluid flow controller 140 for use with a dual fuelheating assembly. The heating unit 70 is functionally similar to theheating units described in U.S. provisional application No. 61/748,071filed Dec. 31, 2012, the entire contents of which are incorporated byreference herein. For example, in many aspects, the heating unit 70 issimilar to that described with reference to FIGS. 22-28 in U.S.provisional application No. 61/748,071.

The heating unit 70 is shown with a pressure switch 60 in fluidcommunication with one of the inputs 15 of the heating unit 70. Thepressure switch 60 can function in a manner as described above.

FIG. 14 shows a heater including the heating unit of FIG. 13 having thepressure switch 60. FIG. 15 shows a schematic diagram of the function ofthe heater of FIG. 14. FIG. 16 shows a schematic diagram of the functionof another embodiment of heater that is similar to those described inU.S. provisional application No. 61/748,071 filed Dec. 31, 2012 andincorporated by reference herein.

In some embodiments, the heating unit 70 can be a fuel selector valve.The fuel selector valve 70 can receive a first fuel or a second fuel. Insome embodiments, the first fuel may be liquid propane gas (LP). In someembodiments, the second fuel may be natural gas (NG). The fuel selectorvalve 70 includes a fuel source connection 12 and a fuel sourceconnection 15. The fuel selector valve 70 can receive LP at fuel sourceconnection 12. The fuel selector valve 70 can receive NG at fuel sourceconnection 15.

In some embodiments, the fuel selector valve 70 can direct fuel to acontrol valve 130. The control valve can include at least one of amanual valve, a thermostat valve, an AC solenoid, a DC solenoid and aflame adjustment motor. The control valve 130 can direct fuel back tothe fuel selector valve 70 and/or to one or more nozzle assemblies 160.In some embodiments the one or more nozzle assemblies 160 can be part ofthe fuel selector valve 70. The nozzle assembly 160 can be similar thevarious embodiments that described in U.S. patent application Ser. No.13/310,664 filed Dec. 2, 2011 and published as U.S. 2012/0255536, theentire contents of which are incorporated by reference herein and are tobe considered a part of the specification. FIGS. 23-24B, 28A-34B,39A-44B, and their accompanying descriptions are but some examples ofnozzle assemblies from U.S. 2012/0255536.

A window or opening 155 can be positioned at the nozzle assembly 160. Anopening 155 can be used to introduce air into the flow of fuel prior tocombustion. The amount of air that is needed to be introduced depends onthe type of fuel used. For example, propane gas needs more air thannatural gas to produce a flame of the same size as will be discussed inmore detail below. In some embodiments, the heating assembly can beswitched between the different fuels without requiring adjustment of awindow or opening for creating the air fuel mixture. Some embodimentscan also include an air shutter assembly around the opening 155. An airshutter can be used to adjust the size of the window. This may be doneto accommodate for differences in fuel quality and/or pressure. In someembodiments, this adjustment can be done once for the system as a whole,but it may not be required to further adjust the air shutter if theheater assembly is switched between different fuels.

The fuel selector valve 70 can also direct fuel to an oxygen depletionsensor (ODS) 180. In some embodiments, the fuel selector valve 70 can becoupled with ODS lines 143 and 144. As shown, the ODS 180 has athermocouple 182 coupled to the control valve 130, and an igniter line184 coupled with an igniter, such as an electrode. In some embodiments,the ODS 180 can be mounted to the main burner 190.

Referring now to FIGS. 17-17A, another embodiment of a fuel selectorvalve 70 will be described. The illustrated fuel selector valve issimilar to that shown in FIGS. 13-14. The fuel selector valve of FIGS.13-14 is also shown with a pressure sensitive switch and can alsoinclude one addition input and output for receiving fuel from thecontrol valve and for directing fuel to a nozzle 160.

The fuel selector valve 70 as illustrated in FIGS. 17-17A includes twopressure regulators 16, one for each different fuel type for a dual fuelheater. Each of the pressure regulators can have a spring loaded valveconnected to a diaphragm. The fluid pressure acting on the diaphragm canmove the valve allowing more or less fluid to flow through the pressureregulator depending on the orientation of the valve with respect to avalve seat which are generally positioned within the flow passagethrough the pressure regulator.

Among other features, the heating assembly can be used to select betweentwo different fuels and to set certain parameters, such as one or moreflow paths, and/or a setting on one or more pressure regulators based onthe desired and selected fuel. The heating assembly 100 can have a firstmode configured to direct a flow of a first fuel (such as LP) in a firstpath through the heating assembly 100 and a second mode configured todirect a flow of a second fuel (such as NG) in a second path through theheating assembly.

The fuel selector valve 70 can be used to select between two differentfuels and to set certain parameters, such as one or more flow paths,and/or a setting on one or more pressure regulators based on the desiredand selected fuel. The fuel selector valve 70 can have a first modeconfigured to direct a flow of a first fuel (such as LPG) on a firstpath through the fuel selector valve 70 and a second mode configured todirect a flow of a second fuel (such as NG) on a second path through thefuel selector valve 70. The fuel selector valve 70 can also include oneor more actuation members. In some embodiments, the fuel selector valve70 can be configured such that inlets of the valve are only open whenthey are connected to a source of fuel, as described in more detailbelow.

FIG. 17 illustrates an external view of a fuel selector valve 70 thatcan have a first inlet 12 and a second inlet 15. Both inlets can have anactuation member with an end that can at least partially enter the inletand close or substantially close the inlet. For example, as illustratedin FIG. 18, the first inlet 12 can have a first actuation member 22 withan end that blocks the inlet. Similarly, the second inlet 15 can have asecond actuation member 24 with an end that blocks the inlet.

As described with respect to various embodiments above, the actuationmembers can have sealing sections 34, 36 that can seat againstrespective ledges to close or substantially close their respectiveinlets 12, 14. Thus, the first actuation member 22 can have a firstposition in which the sealing section 34 of the first actuation memberseats against the first ledge. Similarly, the second actuation member 24can have a first position in which the sealing section 36 of the secondactuation member seats against the second ledge. Each actuation memberpreferably has a biasing member, such as a spring 32 that biases theactuation member toward the first position.

As described in various embodiments above, when a fitting for a sourceof fuel connects to one of the inlets, it can move the actuation memberinto a second position that allows fluid to flow through the inlet. FIG.20 illustrates a fitting 30 of a source of fuel connected to the firstinlet 12. Each of the inlets is shown fluidly connected to a pressureregulator 16 and to the outlet 18.

As with some pressure regulators described above, the pressure settingsof each pressure regulator 16 can be independently adjusted bytensioning of a screw or other device that allows for flow control ofthe fuel at a predetermined pressure or pressure range (which cancorrespond to a height of a spring) and selectively maintains an orificeopen so that the fuel can flow through a spring-loaded valve or valveassembly of the pressure regulator. If the pressure exceeds a thresholdpressure, a plunger seat can be pushed towards a seal ring to seal offthe orifice, thereby closing the pressure regulator. In someembodiments, a fuel selector valve 70 can include two inlets withrespective inlet valves as well as dedicated pressure regulators thatcan direct fluid flow to an outlet. Other embodiments may haveadditional features.

The fuel selector valve can provide additional control of a fluid flowthrough an additional valve system. The fuel selector valve can bothdirect fluid to the control valve 130 and receive a flow of fluid fromthe control valve. As shown, the control valve 130 directs the fluidflow for the oxygen depletion sensor (ODS) to the fuel selector valve.It will be understood that other embodiments can receive both the ODSfluid flow, as well as the nozzle fluid flow, or just the fluid flow forthe nozzle. In addition, the fuel selector valve can direct fluid flowto other components in addition to and/or instead of the control valve130.

As best seen in FIG. 21, the actuators 22, 24 can each be operativelycoupled to a valve member 112, 114 that can open the flow path to eitherthe second outlet 96 or the third outlet 98 114 can be. Thus, fluidreceived at the third inlet 94 can be discharged to either the secondoutlet 96 or the third outlet 98. In this way, the fuel selector valvecan direct fuel to desired location, such as a burner nozzle or ODSnozzle specific for a particular type of fuel.

The actuation members 22, 24 are shown as have three separate movablemembers. For example, actuation member 22 has a first valve 26, amoveable member 102 and a second valve 112. This second valve 112 ofactuation member 22 is also the third valve of the system. Actuationmember 24 is shown with a first valve 28, a moveable member 104 and asecond valve 114. In the overall system, these valves are also calledthe second valve 28 and the fourth valve 112. One benefit of having twoor more independently movable members is that having two or moreseparate members can allow each member to properly seat to therespective valve to prevent leakage; though it will be understood thatone, two, or more members could be used. It can also be seen that anumber of springs 32 and O-rings, 106 can be used to bias the members totheir initial positions and to prevent leakage.

In some embodiments, a fuel selector valve 70 similar to that describedwith respect to FIGS. 17-21 and described further below with respect toFIGS. 22-24B can have a single pressure regulator, or no pressureregulators. In addition, in some embodiments, the fuel selector valve 70can have separate outlets fluidly connected to each inlet and/or fuelhook-up.

Each of the fuel selector valves described herein can be used with apilot light or oxygen depletion sensor, a nozzle, and a burner to formpart of a heater or other gas appliance. The different configurations ofvalves and controls such as by the actuation members can allow the fuelselector valve to be used in different types of systems. For example,the fuel selector valve can be used in a dual fuel heater system withseparate ODS and nozzles for each fuel. The fuel selector valve can alsobe used with nozzles and ODS that are pressure sensitive so that can beonly one nozzle, one ODS, or one line leading to the various componentsfrom the fuel selector valve.

According to some embodiments, a heater assembly can be used with one ofa first fuel type or a second fuel type different than the first. Theheater assembly can include a pressure regulator having a first positionand a second position and a housing having first and second fuelhook-ups. The first fuel hook-up can be used for connecting the firstfuel type to the heater assembly and the second hook-up can be used forconnecting the second fuel type to the heater assembly. An actuationmember can be positioned such that one end is located within the secondfuel hook-up. The actuation member can have a first position and asecond position, such that connecting a fuel source to the heaterassembly at the second fuel hook-up moves the actuation member from thefirst position to the second position. This can cause the pressureregulator to move from its first position to its second position. As hasbeen discussed, the pressure regulator in the second position can beconfigured to regulate a fuel flow of the second fuel type within apredetermined range.

The heater assembly may also include one or more of a second pressureregulator, a second actuation member, and one or more arms extendingbetween the respective actuation member and pressure regulator. The oneor more arms can be configured to establish a compressible height of apressure regulator spring within the pressure regulator.

A heater assembly can be used with one of a first fuel type or a secondfuel type different than the first. The heater assembly can include atleast one pressure regulator and a housing. The housing can comprise afirst fuel hook-up for connecting the first fuel type to the heaterassembly, and a second fuel hook-up for connecting the second fuel typeto the heater assembly. The housing can also include a first inlet, afirst outlet, a second outlet configured with an open position and aclosed position, and a first valve configured to open and close thesecond outlet. A first actuation member having an end located within thesecond fuel hook-up and having a first position and a second positioncan be configured such that connecting a fuel source to the heaterassembly at the second fuel hook-up moves the actuation member from thefirst position to the second position which causes the first valve toopen the second outlet, the second outlet being in fluid communicationwith the second fuel hook-up.

The first actuation member can be further configured such thatconnecting the fuel source to the heater assembly at the second fuelhook-up moves the first actuation member from the first position to thesecond position which causes the at least one pressure regulator to movefrom a first position to a second position, wherein the at least onepressure regulator in the second position is configured to regulate afuel flow of the second fuel type within a predetermined range.

The at least one pressure regulator can comprises first and secondpressure regulators, the first pressure regulator being in fluidcommunication with the first fuel hook-up and the second pressureregulator being in fluid communication with the second fuel hook-up.

Similarly, the first valve can be configured to open and close both thefirst and second outlets or there can be a second valve configured toopen and close the first outlet. The housing may include addition,inlets, outlets and valves. Also a second actuation member may be usedand positioned within the first fuel hook-up.

In certain embodiments, the heater assembly is configured to accept andchannel liquid propane when in a first operational configuration and toaccept and channel natural gas when in a second operationalconfiguration. In other embodiments, the heater assembly is configuredto channel one or more different fuels when in either the first orsecond operational configuration.

The fuel selector valves 70 of FIGS. 17-21 can be used in the systemshown in FIG. 16. Returning to FIGS. 13 and 14, a fuel selector valve 70(also shown in FIGS. 22-24B) can be used in the system shown in FIG. 15.It can be seen that one of the main differences between FIG. 15 and FIG.16 is how the fuel travels from the control valve to the burner. In FIG.16, fuel can travel from the control valve to a pressure sensitivenozzle which can control how the fuel is injected to the burner, i.e.the pathway through the nozzle to the burner.

In FIG. 15, the control valve directs some of the flow directly to theburner through a nozzle and some of the flow is returned to the fuelselector valve 70. This second flow may be directed to the burner by asecond nozzle dependent upon which fuel inlet is connected to a fuelsource. In this way, some of the flow to the burner travels the secondpath when the natural gas connection is made. But, the direct flow tothe burner is independent of whether liquid propane or natural gas isconnected. From this it will be understood that the fuel selector valveof FIGS. 13-14 includes one additional input and an output for receivingfuel from the control valve and for directing fuel to a nozzle, as wellas an internal valve to open and close this passageway.

FIG. 22 illustrates an external perspective view of a fuel selectorvalve 70 that can have an additional input and output and can be used inthe system shown in FIG. 15, although it can also be used in the systemshown in FIG. 16. Like valves described above, valve 70 of FIG. 22 canhave a first fuel source connection or inlet 12 and a second fuel sourceconnection or inlet 15. In some embodiments, the first inlet 12 can beconfigured to connect to a fitting for a first fuel (such as LP), andthe second inlet 15 can be configured to connect to a fitting for asecond fuel (such as NG). Both inlets can have an actuation member withan end that can at least partially enter the inlet and close orsubstantially close the inlet. For example, as illustrated in FIG. 18,the first inlet 12 can have a first actuation member 22 with an end thatblocks the inlet. Similarly, the second inlet 15 can have a secondactuation member 24 with an end that blocks the inlet. FIG. 18 is across-section of the valve illustrated in FIG. 17, but is similar in allrelevant respects to the valve of FIG. 22 if considered to be viewedfrom the line D-D of FIG. 17A.

As described with respect to various embodiments above, the actuationmembers can have sealing sections 34, 36 that can seat againstrespective ledges to close or substantially close their respectiveinlets 12, 14. Thus, the first actuation member 22 can have a firstposition in which the sealing section 34 of the first actuation memberseats against the first ledge. Similarly, the second actuation member 24can have a first position in which the sealing section 36 of the secondactuation member seats against the second ledge. Each actuation memberpreferably has a biasing member, such as a spring 32 that biases theactuation member toward the first position.

As described in various embodiments above, when a fitting for a sourceof fuel connects to one of the inlets, it can move the actuation memberinto a second position that allows fluid to flow through the inlet. FIG.20 illustrates a fitting 30 of a source of fuel connected to the firstinlet 12. Each of the inlets is shown fluidly connected to a pressureregulator 16 and to the outlet 18. FIG. 20 shows the same view as FIG.18.

As with some pressure regulators described above, the pressure settingsof each pressure regulator 16 can be independently adjusted bytensioning of a screw or other device that allows for flow control ofthe fuel at a predetermined pressure or pressure range (which cancorrespond to a height of a spring) and selectively maintains an orificeopen so that the fuel can flow through a spring-loaded valve or valveassembly of the pressure regulator. If the pressure exceeds a thresholdpressure, a plunger seat can be pushed towards a seal ring to seal offthe orifice, thereby closing the pressure regulator. In someembodiments, a fuel selector valve 70 can include two inlets withrespective inlet valves as well as dedicated pressure regulators thatcan direct fluid flow to an outlet. Other embodiments may haveadditional features.

The fuel selector valve can provide additional control of a fluid flowthrough additional valve systems, as described further below. The fuelselector valve can both direct fluid to the control valve 130 andreceive a flow or flows of fluid from the control valve. In someembodiments the control valve 130 directs the fluid flow for the oxygendepletion sensor (ODS) to the fuel selector valve. In some embodiments,the fuel selector valve can receive both the ODS fluid flow as well as aportion of the nozzle fluid flow. In some embodiments, the fuel selectorvalve can receive just the fluid flow for the nozzle from the controlvalve. In addition, the fuel selector valve can direct fluid flow toother components in addition to and/or instead of the control valve 130.For example, in some embodiments the fuel selector valve can selectivelydirect fluid flow to a nozzle. In some embodiments, the fuel selectorvalve can direct fluid flow toward an ODS.

With reference to FIG. 22, the fuel selector valve can have a variety ofconnections allowing for use in the system shown in FIG. 15 and invarious other embodiments of systems described herein. In additional tothe first inlet 12 and second inlet 15, the fuel selector valve can havea third inlet 94 and a fourth inlet 95, each of which can fluidlyconnect to the control valve. The fuel selector valve can also have afirst outlet 18, which can fluidly connect to the pressure regulators 16and the control valve, a second outlet 96 and third outlet 98, which canfluidly connect to an ODS, and a fourth outlet 97, which can fluidlyconnect to a nozzle.

As best seen in FIGS. 24A and 24B, which illustrate the cross sectionsof the fuel selector valve 70 identified in FIG. 23, the actuators 22,24 can each be operatively coupled to a valve member 112, 114 that canadjust flow paths through the selector valve. For example, asillustrated in FIG. 24A, the valve member 112 can selectively allow aflow of fluid that enters through the fourth inlet 95 from the controlvalve to pass through the fourth outlet 97 to the nozzle. In someembodiments, the valve member 112 can have a first position configuredto allow a second fuel (such as NG) to exit the fourth outlet 97 and asecond position configured to block or substantially block a first fuel(such as LP) from exiting the fourth outlet 97. The valve member 112 canbe biased toward the first position. In some embodiments, connecting afitting to the first inlet 12 can move the valve member 112 to thesecond position. Because the second inlet 15 can be configured toreceive fittings for the second fuel (such as NG), when the second inletreceives the second fuel the valve member 112 can be in the firstposition.

Similarly, as illustrated in FIG. 21B, the valve member 114 can direct afluid flow path from the control valve through the third inlet 94 toeither the second outlet 96 or the third outlet 98. In some embodiments,the second outlet can fluidly connect to an ODS pilot for the first fuel(such as LP). In some embodiments, the third outlet can fluidly connectto an ODS pilot for the second fuel (such as NG). In some embodiments,the valve member 114 can be configured to be biased toward a firstposition that allows fluid that enters through the third inlet 94 toflow through the second outlet 96, and that blocks or substantiallyblocks fluid flow through the third outlet 98. In some embodiments,connecting a fitting to the second inlet 15 can move the valve member toa second position that allows fluid that enters through the third inlet94 to flow through the third outlet 98, and that blocks or substantiallyblocks fluid flow through the second outlet 96. Because the first inletcan be configured to receive fittings for the first fuel (such as LP),when the first inlet receives the first fuel the valve member 114 can bein the first position.

As above, in some embodiments, an actuation member 22, 24 may havemultiple separate movable members. For example, actuation member 22 isshown with three separate movable members: a first valve 26, a moveablemember 102, and a second valve 112. This second valve 112 of actuationmember 22 is also the third valve of the system. As a further example,actuation member 24 is shown with two separate movable members: a firstvalve 28 and a second valve 114. In the overall system, these valves arealso called the second valve 28 and the fourth valve 114. One benefit ofhaving two or more independently movable members is that having two ormore separate members can allow each member to properly seat to therespective valve to prevent leakage; though it will be understood thatone, two, or more members could be used for either the first actuationmember or the second actuation member. It can also be seen that a numberof springs 32 and O-rings 106 can be used to bias the members to theirinitial positions and to prevent leakage. Additionally, differentsealing systems can be used. For example, the fourth valve 114 can moverelative to and seal against O-rings 106 to close or substantially closethe valve. The third valve 112 can have a sealing section 116 that seatsagainst a respective ledge to close or substantially close the valve.

Returning now to FIG. 14, in certain embodiments, a control valve 130and/or a heating unit 70, such as a fuel selector valve, can bepositioned to be in fluid communication with the burner 190. The heatingunit 70 and/or control valve 130 can be coupled to the burner 190 in anysuitable manner. As has been discussed, various pipes or lines(including 124, 124A, 124B) can be used to direct fuel flow to a nozzle160 which is then directed to the burner 190. A burner delivery line 148can be used to direct fuel flow from the nozzle(s) to the burner 190.The burner delivery line 148 can be part of, or separate from, theactual burner 190 and may not be used in all embodiments. Thus, it willbe understood that features of the burner delivery line can also befeatures of the burner.

In some embodiments, the burner delivery line 148 defines an opening145A, 145B at a first end thereof through which one or more of thenozzles 160A, 160B can extend (FIG. 14A). In other embodiments, thenozzles are not located within the burner delivery line 148 but arepositioned to direct fuel into the burner delivery line 148. Thenozzle(s) can direct fuel to the venturi 146A, 146B or the throat of theburner, which as shown is constricted to act like a built-in venturi,and then into the burner itself.

In some embodiments, such as that shown in FIG. 14, the burner deliveryline 148 defines an air intake, aperture, opening, or window 155 throughwhich air can flow to mix with fuel dispensed by the nozzle 160A. Anopening 155 can be used to introduce air into the flow of fuel prior tocombustion. The amount of air that is needed to be introduced depends onthe type of fuel used. For example, propane gas at typical pressuresneeds more air than natural gas to produce a flame of the same size. Insome embodiments, the window 155 is adjustably sized. For example, insome embodiments, a cover as part of an air shutter can be positionedover the window 155 to adjust the amount of air that can enter theburner delivery line 148 through the window. The area or volume insideof the burner delivery line 148 at the window 155 defines a mixingchamber where air and fuel can be mixed.

Referring now to FIG. 14A, a schematic cross-section view of a portionof the heater is shown. As shown, in some embodiments, a burner 190 orburner delivery line 148 can have two separate inlets 145A, 145B. Theinlets can be separate and can remain divided along a portion of thelength of the burner or burner delivery line. For example, the burnerdelivery line 148 can be divided from the inlets 145A, 145B until afterthe venturi 146A, 146B. In some embodiments, the end of the separationmay determine the end of the venturi. In some embodiments, the firstinlet 145A can be part of a first conduit, and the second inlet 145B canbe part of a second conduit. The first and second conduits can connectto then form a single conduit, or can both connect to a third conduit.These conduits can all be part of the burner or burner delivery line.

As shown, a window 155 can be positioned between the inlet 145A and theventuri 146A. It can also be seen that the other side does not have awindow. In some embodiments, the burner delivery line 148 can be dividedstarting from the inlets 145A, 145B until after the window 155, or untilafter a set distance from the window. A first fuel that requires moreair (compared to a second fuel) can be injected into the burner deliveryline 148 through nozzle 160A to pass by the window. The second fuel,that does not require as much air, can be injected into the burnerdelivery line 148 through nozzle 160B. In some embodiments, a fuel thatdoes not require as much air can be injected into the burner throughboth nozzles 160A, 160B. Injecting a fuel into both nozzles will resultin a less air rich fuel. It will be understood that the various factorscan be considered to obtain the desired air fuel mixture, including, butnot limited to, nozzle orifice size, window size, position of the nozzlewith respect to the window, position of the second nozzle with respectto the window, etc.

As shown, the burner delivery line can be used in a dual fuel heaterwithout requiring an air shutter, or adjustments to the window size.This can reduce costs and also prevent user error associated withadjusting an air shutter.

As fuel passes the window 155 it will pull air into the mixing chamberof the burner delivery line 148. As the nozzle 160B does not have awindow positioned close to the nozzle, an air/fuel mixture will still becreated at injection, but it will generally not be as air rich as itwould if it were positioned next to a window.

In some embodiments, the first inlet 145A can be positioned a setdistance away from the second inlet 145B. For example, the set distancecan be equal to or greater than the size of the window 155. In someembodiments, the distance from the end of the window to the venturi canbe substantially the same as the distance from the second inlet to theventuri.

It will be understood that though the inlets are shown positioned nextto each other, in some embodiments the two inlets can be more clearlyseparated, or even completely separated, such as having one inlet at oneend of the burner, and the other at an opposite end or different part ofthe burner. In addition, though the illustration shows one inlet with awindow 155 and one without, in other embodiments, both inlets can have awindow, but one window can be substantially larger than the other, suchas 2, 3, 4, or 5 times the size of the first smaller window. It willalso be understood that the window can be any of a number of differentsizes, shapes, and configurations, and may be one or more windows.

Referring to FIGS. 14 and 15, operation of the illustrated heater willbe described according to certain embodiments. A user can connect one oftwo fuels, such as either natural gas or propane to the heater. Eachfuel hook-up can be set for a certain fuel type. Connecting the fuelsource to the fuel selector valve 70 can automatically set the fuelselector valve to a position configured for the particular gas as hasbeen described. If propane is connected to the natural gas inlet, thepressure sensor 60 can detect this pressure difference and prevent thecontrol valve from opening thereby preventing fluid flow to the burner.

With the proper gas is connected and once the pilot has been proven, thesystem can be changed to a heating configuration where fuel can flowfrom the control valve to the burner. The control valve 130 can thencontrol the flow to the pilot (or ODS) 180 and to the burner 190.

In the illustrated embodiment, the control valve 130 returns the pilotfuel flow to the fuel selector valve 70. The setting of the fuelselector valve 70, based on which fuel hook-up is used, then determineswhich pilot nozzle receives the pilot fuel flow.

In the illustrated embodiment, the control valve 130 returns some of theburner fuel flow to the fuel selector valve 70 and some is directed atthe burner nozzle 160A. The setting of the fuel selector valve 70, basedon which fuel hook-up is used, then determines whether burner nozzle160B also receives the burner fuel flow. If the natural gas fuel hook-upis used and natural gas is flowing in the heater, an internal valve inthe fuel selector valve 70 will be open to allow fuel flow to burnernozzle 160B. If the propane fuel hook-up is used and propane gas isflowing in the heater, an internal valve in the fuel selector valve 70will be closed to prevent fuel flow to burner nozzle 160B. But, withpropane, as with natural gas, fuel can flow from the control valve 130to the burner nozzle 160A.

It can be seen that one of the main differences between FIG. 15 and FIG.16 is how the fuel travels from the control valve to the burner. In FIG.16, fuel can travel from the control valve to a pressure sensitivenozzle which can control how the fuel is injected to the burner, i.e.the pathway through the nozzle to the burner.

In FIG. 15, the control valve directs some of the flow directly to theburner through a nozzle and some of the flow is returned to the fuelselector valve 70. This second flow may be directed to the burner by asecond nozzle dependent upon which fuel inlet is connected to a fuelsource. In this way, some of the flow to the burner travels the secondpath when the natural gas connection is made. But, the direct flow tothe burner is independent of whether liquid propane or natural gas isconnected. From this it will be understood that the fuel selector valveof FIGS. 13-14 includes one addition input and an output for receivingfuel from the control valve and for directing fuel to a nozzle, as wellas an internal valve to open and close this passageway.

Turning now to FIGS. 25A-25B, another embodiment of a pressure switch 60is illustrated. The pressure switch 60 has a housing 62 having an inlet68 to receive fluid to be able to respond to certain pressures. Asshown, the pressure switch 60 is a normally open pressure switch. Thepressure switch 60 can be set to close when a greater than desiredpressure encounters a valve member 58, such as the illustrated diaphragm58. A spring 64 can be used to determine the pressure required to movethe diaphragm 58.

As can be seen, in this pressure switch, rather than control anelectrical connection, the valve member can control a flow path throughthe pressure switch between an inlet 61 and an outlet 63. A valve stem65 on the valve member 58 can engage a valve seat 67 on the housing 62to close the flow path when the pressure of the fluid entering inlet 68is at or above a set threshold pressure. The inlet 68 may also beconsidered a pressure chamber. Other types and styles of valve memberscan also be used. For example, the diaphragm 58 alone can be used toclose the flow path. In addition, in other embodiments, the pressureswitch 60 can be a normally closed pressure switch that is opened whenthe pressure in the inlet or pressure chamber 68 is at or above a setthreshold pressure.

The pressure switch 60 with flow path control can be used to control oneor more flows of fuel within a heating assembly. For example, thepressure switch 60 can be in fluid communication with an inlet on theheating assembly such that the pressure at the pressure chamber 68 isthe delivery pressure of the fluid. As different types of fuels aregenerally provided within distinguishable pressure ranges, as has beendiscussed, the pressure switch can be used to distinguish betweendifferent types of fuel. The pressure switch may be used as a safetyfeature, similar to other pressure switches and devices discussedherein, but may also serve other or additional purposes, such asdetermining one or more flow paths through the heating assembly.

FIGS. 26-29B show an example of a heater 110 having a pressure switch 60with flow path control. The heater 110 of FIG. 26 is very similar to theheater shown in FIG. 14. Looking now at FIG. 27A, the heater 110 isshown in a partially dissembled view. The illustrated heating source 70of the heater 110 is the same as that shown and described with respectto FIGS. 22-24B and FIG. 14. Thus, the primary difference between theheater 110 and the heater shown in FIG. 14 is the use of a differentpressure switch. In the embodiment of FIGS. 26-29B, the pressure switch60 provides flow path control to the pilot or ODS 180 based on thedelivery pressure of the fuel at one of the inlets.

FIGS. 27A, 28A and 29A are partially dissembled views of the heater ofFIG. 26 illustrating different flow configurations and FIGS. 27B, 28Band 29B respectively show a schematic diagram of the flow configurationof one of FIGS. 27A, 28A and 29A. FIGS. 27A-B show the flow pathsthrough the heater when a natural gas (NG) supply is connected to thenatural gas input 15. It will be understood that the illustrated NG andliquid propane (LPG) inputs and supplies are simply examples of fuelsthat can be used with the heater.

As shown, when NG is connected to the NG inlet 15, the pressure chamber68 of the pressure switch 60 is in communication with the fuel as it isdelivered to the heater. Thus, the delivery pressure of the gasdetermines the position of the internal valve member 58. The valve canbe configured such that NG delivered within a standard or typicalpressure range does not move the valve member so that the flow pathbetween the inlet 61 and the outlet 63 is open and fuel can flow throughthe flow path. The NG ODS or pilot line 144 has been divided into twosegments 144A and 144B with the pressure switch 60 in-between. In thisposition, the pressure switch 60 can determine whether NG fuel can flowto the pilot or ODS 180. As will be described in more detail below, whenan incorrect fuel is connected to the NG inlet with a higher deliverypressure, the pressure switch can prevent this gas from flowing to thepilot 180. Thus, the pilot cannot be proven and fuel cannot flow to theburner.

Though the schematic diagram has been drawn slightly differently fromFIG. 15, the other flow paths through the heater and between the controlvalve 130, heating source 70, ODS 180, and nozzle(s) 160 are the same asthose previously described.

FIGS. 28A-B show an LP fuel source connected to the LP inlet 12. The LPinlet 12 is not in communication with the pressure switch 60, thus, thedelivery pressure does not control any of the flow paths through theheater.

FIGS. 29A-B show an LP fuel source connected to the NG inlet 15. Asshown, when LP is connected to the NG inlet 15, the pressure chamber 68of the pressure switch 60 is in communication with the fuel as it isdelivered to the heater. Thus, the delivery pressure of the gasdetermines the position of the internal valve member 58. The valve canbe configured such that LP delivered within a standard or typicalpressure range moves the valve member so that the flow path between theinlet 61 and the outlet 63 is closed and fuel cannot flow through theflow path. The NG ODS or pilot line 144 has been divided into twosegments 144A and 144B with the pressure switch 60 in-between. In thisposition, the pressure switch 60 can determine whether fuel can flow tothe pilot or ODS 180. As LP is the incorrect fuel in this instance,because it in is connected to the incorrect NG inlet and it has a higherdelivery pressure than NG, the pressure switch can prevent LP fromflowing to the pilot 180 in this situation. Thus, the pilot cannot beproven and LP fuel cannot flow to the burner through incorrect flowpaths. Thus, a user can be prevented from causing a safety hazard thatmay result if the wrong fuel where connected to the wrong inlet or fuelhook-up of the heater.

Though the pressure switch 60 is shown configured to control flowthrough one of the ODS lines, it will be understood that the pressureswitch 60 could also be positioned in other locations to control otherflows. For example, the pressure switch could be used to control flow tothe burner, positioned for example at a point along the NG gas line124B. In this way, the pressure switch could allow the heater to stillbe used when LP is connected to the NG inlet, but would only allow flowto the LP burner nozzle.

In another embodiment, the pressure switch 60 can be used on a dual fuelheater with a single inlet, such as with a changeable pressure regulatorto a two position pressure regulator. The pressure switch can include arocker valve, instead of the on/off valve and can be used to determinethe flow path to the pilot or ODS. Thus, the pressure switch can havetwo alternate outlets instead of a single outlet 63. One outlet candirect fuel to a first pilot, first pilot nozzle, or first orifice andthe second outlet can direct fuel to a second pilot, second pilotnozzle, or second orifice. For example the first nozzle pilot can beconfigured for NG and the second for LP.

In addition, the pressure switch 60 with flow control could be used on asingle fuel heater, such as an NG heater. The pressure switch may bepositioned along a flow path directed towards the pilot, ODS, burner, orcontrol valve, among other features.

Moving now to FIGS. 30-33B an embodiment of a heating source 70 is shownthat incorporates a pressure switch 60 with flow control into thehousing of the heating source. The heating source can function in amanner similar to those previously described. For example, the heatingsource of FIGS. 30-33B can be the same as that described with respect toFIGS. 22-24B with the addition of the pressure switch 60. Of course itwill be understood that the pressure switch 60 can also be used withand/or integrated into other heating sources as well. In addition, othertypes of pressure switches may be integrated into the heating source,for example, a pressure switch with electronic control can be integratedinto the heating source.

Thus, in some embodiments a fuel source can connect to either inlet 12or inlet 15. Selecting the inlet can determine which pressure regulator16 will be used as well as selecting certain flow paths through theheating source 70. From the pressure regulator, the fuel can exit atoutlet 18 to the control valve 130. The control valve 130 can direct aflow of fuel for the pilot or ODS to the inlet 94 and a flow of fuel forthe burner to the inlet 95. Depending on whether the inlet 12 or theinlet 15 is selected can determine whether fuel will flow to the burnerfrom outlet 97. Also, depending on whether the inlet 12 or the inlet 15is selected can determine whether the pilot flow will exit outlet 96 or98.

If the inlet 15 has been selected, then the delivery pressure of thefuel and the pressure switch 60 can also determine whether fuel can flowto the pilot. Looking now at FIGS. 32-33B, the details of the pressureswitch can be seen. In FIG. 32A the inlet 68 can be seen that allowsfluid communication between fuel at the inlet 15 and the valve 58 of thepressure switch. If the delivery pressure exceeds a predeterminedthreshold pressure, the valve 58 can be moved from a first position to asecond position. In the illustrated embodiment, this can close the flowpath between inlet 61 and outlet 63 as best seen in FIG. 33B. Inlet 61of the pressure switch 60 can be connected to the inlet 94 of theheating source 70 and outlet 63 of the pressure switch 60 can beconnected to the outlet 98 of the heating source 70. A separate valvecan be used to determine whether the inlet 94 is open to the outlet 96or the outlet 98 as has been described with respect to previousembodiments.

According to some embodiments, a heater assembly can comprise a burner,a pilot light, a gas hook-up, a control valve and a pressure switch. Thecontrol valve can be configured to receive a flow of fuel from the gashook-up and to selectively direct fuel to the pilot light and theburner. The pressure switch can be in fluid communication with the gashook-up and be movable at a predetermined threshold pressure from afirst position to a second position. The pressure switch can be furtherconfigured such that if a fuel is connected to the gas hook-up that hasa delivery pressure either above or below the predetermined thresholdpressure, the fuel will act on the pressure switch to move it from thefirst position to the second position.

The movement from the first position to the second position results in achange in the heater assembly. This change can be a safety feature, suchas to prevent the wrong fuel from flowing through the heater assemblythrough the wrong flow paths, but may also provide a control mechanism,such as determining a flow path through the heater assembly. In someembodiments, the movement of the pressure switch prevents that the pilotlight from being proven to thereby prevent the fuel from flowing to theburner. This may be a result of a change in the electrical system or achange in the flow of fuel through the system.

In some embodiments, the pressure switch can comprise a valve member,first and second electrical contacts, and a movable contact membermechanically connected to the valve member and movable therewith. Themovable contact member can be configured for electrical connection tothe first and second electrical contacts when in a first engagedposition and having a second disengaged position configured to create anopen circuit. The electrical contacts can be used with a thermocouple,igniter, printed circuit board, and/or control valve, among otherfeatures. For example, in some embodiments, the movable contact memberof the pressure switch is in the second disengaged position when thedelivery pressure is above a predetermined threshold pressure to createan open circuit between the thermocouple and the control valve such thatthe control valve cannot flow fuel to the burner.

In some embodiments, the pressure switch can be used to control whetheran electric signal can flow to the igniter. In still other embodiments,the pressure switch comprises a valve member positioned within a flowchannel and movement of the pressure switch either opens or closes theflow channel. The pressure switch can allow or prevent flow to the pilotor to the burner in some embodiments.

According to some embodiments, a heater assembly can comprise a pilotlight, a burner, a first gas hook-up, a control valve configured toreceive a flow of fuel from the first gas hook-up and to selectivelydirect fuel to the pilot light and the burner, and a pressure switch influid communication with the first gas hook-up. The pressure switch cancomprise a valve member movable at a predetermined threshold pressure,first and second electrical contacts, and a movable contact membermechanically connected to the valve member and movable therewith. Themovable contact member can be configured for electrical connection tothe first and second electrical contacts when in a first engagedposition and have a second disengaged position configured to create anopen circuit. The pressure switch can be configured such that if a fuelis connected to the first gas hook-up that has a delivery pressureeither above the predetermined threshold pressure in one situation, orbelow the predetermined threshold pressure in another situation, thefuel will act on the pressure switch to move the movable contact memberfrom one of the first or second positions to the other position suchthat the pilot light cannot be proven to thereby prevent the fuel fromflowing to the burner.

The contact member can contact two electrical connection members whichcan be electrically connected to a printed circuit board, igniter,igniter switch, control valve and/or thermocouple, among other features.

In some embodiments, a heater assembly can comprise a housingcomprising: a first gas hook-up, a first pressure regulator, a firstflow path extending between the first gas hook-up and the pressureregulator, a second flow path, and a pressure switch in fluidcommunication with the first gas hook-up upstream from the firstpressure regulator. The pressure switch can be movable from a firstposition to a second position when a delivery pressure of a fuel at thefirst gas hook-up is within a predetermined delivery pressure range. Thepressure switch can be configured such that if the fuel connected to thefirst gas hook-up has a delivery pressure within the predetermineddelivery pressure range, the fuel will act on the pressure switch tomove it from the first position to the second position which movementopens or closes the second flow path through the housing.

Although this invention has been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. In addition, while a number of variations of the invention havebeen shown and described in detail, other modifications, which arewithin the scope of this invention, will be readily apparent to those ofskill in the art based upon this disclosure. It is also contemplatedthat various combinations or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the invention. Accordingly, it should be understood thatvarious features and aspects of the disclosed embodiments can becombined with or substituted for one another in order to form varyingmodes of the disclosed invention. Thus, it is intended that the scope ofthe present invention herein disclosed should not be limited by theparticular disclosed embodiments described above, but should bedetermined only by a fair reading of the claims that follow.

Similarly, this method of disclosure, is not to be interpreted asreflecting an intention that any claim require more features than areexpressly recited in that claim. Rather, as the following claimsreflect, inventive aspects lie in a combination of fewer than allfeatures of any single foregoing disclosed embodiment. Thus, the claimsfollowing the Detailed Description are hereby expressly incorporatedinto this Detailed Description, with each claim standing on its own as aseparate embodiment.

What is claimed is:
 1. A heater assembly for use with one of a firstfuel type or a second fuel type different than the first, the heaterassembly comprising: a burner; a pressure regulator unit configured toregulate either a fuel flow of a first fuel type within a firstpredetermined range or of a second fuel type within a secondpredetermined range different from the first, the pressure regulatorunit comprising a housing having first and second fuel hook-ups, thefirst fuel hook-up for connecting the first fuel type to the heaterassembly and the second hook-up for connecting the second fuel type tothe heater assembly; a pilot nozzle; a temperature sensor; a controlvalve for controlling the flow of said first type of fuel and the flowof said second type of fuel to said burner; a pressure switchcommunicating with one of said first and second fuel hook-ups, whereinwhen fuel has a pressure below a threshold said pressure switch permitssaid temperature sensor to electrically connect with said control valveand when a fuel has above said pressure threshold said pressure switchprevents said temperature sensor from electrically connecting with saidcontrol valve.